KR101874560B1 - Piston for vehicle engine and method for manufacturing the same - Google Patents

Abstract

A method for manufacturing a piston for a vehicle engine according to the present invention is a piston manufacturing method for a vehicle engine including a first piston portion having at least two contact surfaces spaced from each other and extending in the circumferential direction, a joining member and at least two abutting surfaces spaced from each other and extending in the circumferential direction A piston assembly step of assembling a second piston part to form a piston assembly, a piston welding step of heating the assembled piston assembly to weld the first piston part, the joining member and the second piston part in an open atmosphere, And a piston cooling step of cooling the piston unit formed by welding the first piston part, the joining member, and the second piston part, wherein the piston assembly has a position where the assembled position of the first piston part and the second piston part is maintained , Wherein in the cooled piston unit, the engaging portion is removed The engagement portion removing step; further comprises a.

Description

TECHNICAL FIELD [0001] The present invention relates to a piston for a vehicle engine and a method for manufacturing a piston for a vehicle engine,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston for a vehicle engine and a method for manufacturing a piston for a vehicle engine, and more particularly to a piston for a vehicle engine in which a cooling gallery is formed and a method of manufacturing the same.

In the case of a steel-made piston used in an automotive internal combustion engine, a cooling gallery is formed to rapidly cool high heat generated in the combustion process of the fuel, thereby preventing the piston from being damaged.

A lower piston in which a piston skirt and a piston pinhole are formed are separately prepared and the upper piston and the lower piston are welded to each other to form a cooling gallery, Thereby forming the cooling gallery.

As a method for welding the upper piston part and the lower piston part to each other, various methods such as friction welding and brazing have been proposed.

US Patent No. 6,260,472 discloses a process for manufacturing a steel piston by friction welding. However, in the process of welding the upper piston portion and the lower piston portion by friction welding, flashing occurs, There is a problem that the flash is left inside the cooling gallery, thereby interfering with the fluid flow inside the cooling gallery.

U.S. Patent No. 8,991,046 discloses a process for manufacturing a steel piston by brazing, but there is a problem that productivity is lowered as heating and cooling are performed in a closed chamber.

Disclosure of Invention Technical Problem [8] The present invention has been made based on the technical background as described above, and proposes a method of manufacturing a piston for a vehicle engine and a piston for a vehicle engine that can improve productivity.

A method for manufacturing a piston for a vehicle engine according to an aspect of the present invention is a method for manufacturing a piston for a vehicle engine, the method comprising: a first piston portion having at least two abutting surfaces spaced from each other and extending in the circumferential direction; A piston assembly step of assembling a second piston part spaced apart and having at least two circumferentially extending contact surfaces to form a piston assembly; A piston welding step of heating the assembled piston assembly to weld the first piston part, the joining member and the second piston part in an open atmosphere; And a piston cooling step of cooling the piston unit formed by welding the first piston unit, the joining member, and the second piston unit, wherein the piston assembly includes a first piston unit, a second piston unit, Further comprising a retaining portion for retaining the retaining portion in the cooling piston unit, and removing the retaining portion in the cooled piston unit.

The latching part may be formed on one of the first piston part and the second piston part, and the latching part may protrude to surround a part of the piston part where the latching part is not formed.

The engaging portion may include a rim adjacent to the first abutment surface disposed on the center side of the first piston portion or the second piston portion, of the pair of abutment surfaces formed on the first piston portion or the second piston portion, And may be formed so as to protrude in a direction intersecting with a plane formed by the bonding surface.

It is preferable that the engaging portion includes a first contact surface disposed on the center side of the first piston portion or the second piston portion and a second contact surface spaced apart from the first contact surface, And may be protruded in a direction intersecting the plane formed by the joining surface.

A first round portion having a predetermined radius of curvature is formed between the engaging portion and the first abutting surface or between the engaging portion and the second abutting surface, and the first round portion facing the round portion, A cut portion formed in a slanting line or a second round portion having a predetermined radius of curvature may be formed at an edge portion of the piston portion.

In addition, the radius of curvature of the second round portion may be larger than the radius of curvature of the first round portion.

The engaging portion may be detachably provided with respect to the first piston and the second piston, and the engaging portion may include an engaging portion formed in an annular shape and having a through hole formed at the center thereof, The outer diameter of the body is defined by a first piston side joint surface edge adjacent to a joint surface disposed on the center side of the joint surfaces of the first piston portion and a second piston joint surface edge adjacent to a joint surface disposed on the center side of the joint surfaces of the second piston portion And the outer circumferential surface of the engaging portion is formed in a shape corresponding to the first piston side joint surface rim and the second piston side joint surface side in the state that the engaging portion is disposed in the piston assembly Can be simultaneously brought into contact with the joining surface rim.

The engaging portion is disposed on the side of the combustion cavity, the one side of the engaging portion is disposed in parallel to one surface of the first piston, May be supported by the second piston portion.

The piston welding step may include a piston manufacturing device including a heating space partially opened, heating means for providing heat inside the heating space, and moving means moving in one direction within the heating space, In the piston welding step, the piston assembly can be heated by the moving means while being moved at a predetermined speed in one direction in the heating space.

The piston welding step may include a preheating step of heating the piston assembly assembled at room temperature from the room temperature to a preheating temperature lower than the melting temperature of the joining member; And heating the piston assembly heated up to the preheating temperature in the preliminary heating step to a main heating temperature higher than the melting temperature of the joining member so that the first piston portion of the piston assembly, And a main heating step of welding the piston parts to each other.

The second piston portion includes a piston skirt and a piston pinhole, and the first piston portion, the joining member, and the second piston portion are stacked in this order to form the piston assembly, and the plurality of piston assemblies Can be continuously moved by the moving means.

A piston for a vehicle engine according to another aspect of the present invention is a method for manufacturing a piston for a vehicle engine, comprising a first piston portion having at least two contact surfaces spaced from each other and extending in the circumferential direction, Assembling a second piston portion having at least two circumferentially extending contact surfaces to form a piston assembly; A piston welding step of heating the assembled piston assembly to weld the first piston part, the joining member and the second piston part in an open atmosphere; And a piston cooling step of cooling the piston unit formed by welding the first piston unit, the joining member, and the second piston unit, wherein the piston assembly includes a first piston unit, a second piston unit, And a retaining portion for retaining the retaining portion in the cooling piston unit, wherein the retaining portion is removed from the cooled piston unit.

As described above, according to the embodiment of the present invention, it is possible to provide a vehicle engine piston and an automobile engine piston manufacturing method in which productivity is improved, thereby making it possible to manufacture a large number of pistons for a vehicle engine with less cost or time .

1 is a cross-sectional view of a piston for a vehicle engine according to an embodiment of the present invention.
FIG. 2 is a view showing a state before the upper piston part and the lower piston part of the vehicle engine piston of FIG. 1 are assembled.
FIG. 3 is a view showing a piston assembly in which the upper piston portion, the lower piston portion, and the joining member of FIG. 2 are assembled.
4 is an enlarged view of the portion VI in Fig.
Fig. 5 is a view showing the joining member of Fig. 1. Fig.
6 is a view showing a process in which the piston assembly of FIG. 3 is welded in the piston manufacturing apparatus.
7 is a view showing an internal temperature distribution of the piston manufacturing apparatus of FIG.
8 is a cross-sectional view of the piston assembly held by the jig when the piston assembly is seated in the piston manufacturing apparatus of Fig. 6;
Fig. 9 is a view showing the metal texture size of the piston before and after the piston manufacturing process by the piston manufacturing apparatus of Fig. 6; Fig.
Fig. 10 is a view showing a cooling gallery of a piston unit formed by welding a piston assembly in the piston manufacturing apparatus of Fig. 6;
11 is an enlarged view of the portion XII in Fig.
12 is a view illustrating a method of manufacturing a piston for a vehicle engine according to an embodiment of the present invention.
13 is a view showing a state in which a piston assembly is assembled in a process of manufacturing a piston for a vehicle engine according to another embodiment of the present invention.
14 is a view showing a state in which a piston assembly is assembled in a process of manufacturing a piston for a vehicle engine according to another embodiment of the present invention.
15 is an enlarged view showing the XV portion of FIG.
16 is a view showing a state in which a piston assembly is assembled in a process of manufacturing a piston for a vehicle engine according to another embodiment of the present invention.
17 is a view showing a state in which a piston assembly is assembled in a process of manufacturing a piston for a vehicle engine according to a method for manufacturing a piston for a vehicle engine according to another embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains.

The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification. In addition, since the sizes and thicknesses of the respective components shown in the drawings are arbitrarily shown for convenience of explanation, the present invention is not necessarily limited to those shown in the drawings.

The term " on " in the present invention means to be located above or below the object member, and does not necessarily mean that the object is located on the upper side with respect to the gravitational direction. Also, throughout the specification, when an element is referred to as " including " an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise.

Hereinafter, a method for manufacturing a piston for a vehicle engine and a piston for a vehicle engine according to embodiments of the present invention will be described in detail with reference to the drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains.

The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification. In addition, since the sizes and thicknesses of the respective components shown in the drawings are arbitrarily shown for convenience of explanation, the present invention is not necessarily limited to those shown in the drawings.

The term " on " in the present invention means to be located above or below the object member, and does not necessarily mean that the object is located on the upper side with respect to the gravitational direction. Also, throughout the specification, when an element is referred to as " including " an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise.

Hereinafter, a method for manufacturing a piston for a vehicle engine and a piston for a vehicle engine according to embodiments of the present invention will be described in detail with reference to the drawings.

1 is a cross-sectional view of a piston for a vehicle engine according to an embodiment of the present invention.

1, a piston 1 for a vehicle engine according to an embodiment of the present invention includes a first piston (not shown) made of a forged steel such as precipitation hardening type ferrite perlite steel (AFP steel) or a heat treated steel such as 42CrMo4 And a piston body 100 formed by welding a first piston portion 110 (see FIG. 2) and a second piston portion 120 (see FIG. 2). Inside the upper portion of the piston body 100, A cooling gallery 140 for cooling the high temperature generated in the process is formed. A pin hole 126 is formed in the lower portion of the piston body 100 to receive the piston skirt 125 and the piston pin (not shown).

In order to form the cooling gallery 140 of the piston 1 for a vehicle engine according to the embodiment of the present invention, a plurality of joint surfaces are respectively formed in the first piston portion 110 and the second piston portion 120, The cooling glaze 140 is formed inside the piston body 100 by joining the facing surfaces of the opposed first piston portion 110 and the second piston portion 120 together.

Fig. 2 is a view showing a state before the upper piston part and the lower piston part of the vehicle engine piston of Fig. 1 are assembled, and Fig. 3 is a view showing a piston assembly in which the upper piston part, the lower piston part, FIG. 4 is an enlarged view of the portion VI in Fig. 3, and Fig. 5 is a view showing the joining member in Fig.

2 to 5, the first piston unit 110 forms an upper side of the piston 1, a combustion cavity 115 is formed at the center of the first piston unit 110, A first bonding surface 112 and a second bonding surface 113 are formed on the lower surface of the portion 110 and extend in the circumferential direction. A first groove (114) is formed between the first bonding surface (112) and the second bonding surface (113). The second abutment surface 113 is disposed on the center side of the first piston portion 110, that is, inwardly with respect to the first abutment surface 112.

The second piston portion 120 forms the lower side of the piston 1 and the second piston portion 120 is formed with the piston skirt 125 and the piston pinhole 126.

On the upper surface of the second piston portion 120, similarly to the first piston portion 110, a third joint surface 122 and a fourth joint surface 123 spaced from each other and extending in the circumferential direction are formed, The second groove 124 is recessed between the third bonding surface 122 and the fourth bonding surface 123. The fourth abutment surface 123 is disposed on the center side of the second piston portion 120, that is, inwardly with respect to the third abutment surface 122.

On the edge side of the third joint surface 122 spaced apart from the second groove 124, a latching portion 127 is protruded upward. The engaging portion 127 is formed in a circumferential direction, that is, an annular shape, and the outer diameter of the engaging portion 127 is formed to have a size corresponding to the diameter of the combustion cavity 115 formed through the center of the first piston portion 110 .

When the first piston portion 110 and the second piston portion 120 are assembled before and after welding the engaging portion 127 of the second piston portion 120 is engaged with the combustion cavity 115 of the first piston portion 110 So that the first piston portion 110 and the second piston portion 120 are mutually mated with each other by covering a portion of the first piston portion 110 and more specifically the inner rim of the first piston portion 110. [ Can be maintained.

On the other hand, the first cutting portion 118 is formed obliquely on the inner edge of the first piston portion 110, that is, on the inner end side of the second abutment surface 113, and the fourth joint 118 of the second piston portion 120, A round portion 128 having a predetermined radius of curvature, for example, a radius of curvature of 0.2 mm to 0.7 mm, is formed at a portion where the surface 123 and the engaging portion 127 are connected. A second cutting portion 129 is formed at an upper end portion of the engaging portion 127 in a slanting direction toward the inner edge side of the first piston portion 110.

It is possible to suppress interference between the first piston portion 110 and the second piston portion 120 in the assembling process by the first cutting portion 118, the second cutting portion 129 and the round portion 128 So that assembly and welding between the first piston portion 110 and the second piston portion 120 can be smoothly performed.

The locking part 127 is formed on the inner side of the second piston part 120. The locking part 127 may be formed on the first piston part 110 or the first piston part 110 or the outer rim of the second piston portion 120 is also possible.

The joining member 130 is disposed between the first piston portion 110 and the second piston portion 120 in a state where the first piston portion 110 and the second piston portion 120 are assembled before welding.

The joining member 130 includes a joining member body 131 formed in a circular plate shape and the through hole 132 is formed at the center of the joining member body 131. [ The joining member 130 may be formed of, for example, a nickel-based alloy material. In this embodiment, the bonding member 130 may be formed of ternary nickel filler metal, and may be provided in the form of a metal thin film having a thickness of, for example, 50 μm to 200 μm.

The diameters of the connecting member body 131 are formed to correspond to the lower surface of the first piston portion 110 and the upper surface diameter of the second piston portion 120. The diameter of the through hole 132 is larger than the diameter of the second piston 120 The diameter of the engaging portion 127 formed on the outer circumferential surface of the engaging portion 127. [ Therefore, when the piston assembly is assembled with the first piston portion 110, the joint member 130, and the second piston portion 120, the engagement interference of the engagement member 120 by the engagement portion 127 Can be suppressed.

The first piston part 110 and the second piston part 130 are assembled to form the piston assembly and the first piston part 110 is formed on one surface of the joint member 130. [ The first joint surface 112 and the second joint surface 113 are in contact with each other and the third joint surface 122 and the fourth joint surface 123 of the second piston portion 120 are connected to the back surface of the joint member 130, Respectively. The first joining face 112 and the second joining face 113 are disposed such that the third joining face 122 and the fourth joining face 123 face each other with the joining member 130 interposed therebetween. A part of the joining member 130 is positioned between the first groove 114 of the first piston portion 110 and the second groove 124 of the second piston portion 120.

When the joint surfaces 112, 113, 122 and 123 are welded to each other by heating and welding the first piston portion 110, the joint member 130 and the second piston portion 120, the first piston portion The first groove 114 of the second piston portion 110 and the second groove 124 of the second piston portion 120 form a cooling gallery 140. At this time, a part of the joining member 130, which is disposed between the first groove 114 and the second groove 124, is diffused to the inside of the cooling gallery 140, The diffusion layer 150 (see FIG. 10) containing the nickel-based alloy can be formed.

Hereinafter, the process of manufacturing the piston 1 according to the embodiment of the present invention will be described in detail.

FIG. 6 is a view showing a process in which the piston assembly of FIG. 3 is welded in a piston manufacturing apparatus, and FIG. 7 is a view showing an internal temperature distribution of the piston manufacturing apparatus of FIG.

Hereinafter, the piston assembly described herein refers to a state in which the first piston portion 110, the joining member 130, and the second piston portion 120 are assembled together before welding, and the piston unit includes the piston assembly The first piston 110 and the second piston 120 are welded to each other through the heating process in the piston manufacturing apparatus 200 (see FIG. 6).

6 and 7, the piston manufacturing apparatus 200 for manufacturing the piston 1 according to the present embodiment includes a heating space (Z ₁ , Z ₂ ) in which a part is opened and a heating space cooling space and the production apparatus body 210 that includes (Z _3, Z _4), and the heating area (Z _1, Z ₂₎ the heating means (230) for providing heat to the inside of, to which the piston assembly mounted through the heating area (Z _1, Z ₂₎ and the cooling area (Z _3, Z ₄₎ in the state includes a moving unit 220 which moves in one direction.

The heating spaces Z ₁ and Z ₂ are formed in an open atmosphere by communicating with the outside of the piston manufacturing apparatus 200 through the first openings 211 and through the second openings 212 to the cooling spaces Z ₃ , Z ₄ ). That is, the heating spaces Z ₁ and Z ₂ are formed by a heating furnace in which a part is opened.

At this time, the first opening 211 and second opening 212 is heated area (Z _1, Z ₂₎ some areas of the size that can be not to open as a whole, the moving means 220 and the piston assembly move May be formed in an open state.

The heating spaces Z ₁ and Z ₂ include a preheating space Z ₁ and a main heating space Z ₂ communicating with each other. The preheating space Z ₁ is positioned adjacent to the front side of the heating spaces Z ₁ and Z ₂ and the first opening 211 and the main heating space Z ₂ is located adjacent to the _first heating space Z ₁ And is disposed on the rear side.

The preliminary heating space Z ₁ includes a plurality of sub preliminary heating spaces Z ₁₁ , Z ₁₂ , Z ₁₃ and Z ₁₄ arranged in the moving direction of the moving means 220.

Similarly, the main heating space Z ₂ includes a plurality of sub-main heating spaces Z ₂₁ , Z ₂₂ , Z ₂₃ , Z ₂₄ arranged in the moving direction of the moving means 220.

The heating means 230 provides high heat generated by electric or combustion to the heating spaces Z ₁ and Z ₂ and includes a plurality of heating units 231 to 238. The piston assemblies, which move the heating spaces Z ₁ , Z ₂ at a predetermined speed by the heat supplied from the heating means 230, can be preheated continuously and then welded.

At this time, the plurality of heating units (231-238) are a plurality of sub preheating space each _{(Z 11, Z 12, Z} 13, Z 14) and a plurality of sub-main heating space (Z _21, Z _22, Z _23, Z ₂₄ , respectively, and one heating unit 231 to 238 is provided for each of the sub preheating spaces Z ₁₁ , Z ₁₂ , Z ₁₃ , Z ₁₄ and sub main The internal temperatures of the heating spaces Z ₂₁ , Z ₂₂ , Z ₂₃ , and Z ₂₄ may be differently formed. The one-way length of each of the sub preheating spaces Z ₁₁ , Z ₁₂ , Z ₁₃ and Z ₁₄ and the sub-main heating spaces Z ₂₁ , Z ₂₂ , Z ₂₃ and Z ₂₄ , May be formed to have the same length. Therefore, during the movement of the piston assembly by the moving means 220, the sub preheating spaces Z ₁₁ , Z ₁₂ , Z ₁₃ and Z ₁₄ and the sub-main heating spaces Z ₂₁ , Z ₂₂ and Z ₂₃ , Z ₂₄ ) are the same.

In this embodiment, the internal temperature of the first sub-preheating space Z ₁₁ of the sub-preheating spaces Z ₁₁ , Z ₁₂ , Z ₁₃ , and Z ₁₄ is illustratively the first preheating temperature (Temp ₁ ) , The internal temperature of the second sub-preheating space Z ₁₂ is the second preheating temperature Temp _{2 and} the internal temperature of the third sub-preheating space Z ₁₃ is the second preheating temperature Temp ₂ , And the internal temperature of the fourth sub-preheating space Z ₁₂ may be formed at the _third preheating temperature (Temp ₃ ).

(Temp ₁ ), the second preheating temperature (Temp ₂ ), and the third preheating temperature (Temp ₃ ). The first preheating temperature Temp ₁ , the second preheating temperature Temp ₂ and the third preheating temperature Temp ₃ are formed to be lower than the melting temperature of the joining member 130 and the third preheating temperature Temp ₃ are formed close to the melting temperature of the joining member 130.

Illustratively, the first pre-heating temperature (Temp ₁ ) is greater than 500 degrees Celsius and less than 800 degrees Celsius, the second preheating temperature (Temp ₂ ) and the third preheating temperature (Temp ₃ ) Lt; RTI ID = 0.0 > 1200 C. < / RTI >

That is, by preheating the piston assembly in the preliminary heating spaces Z ₁₁ , Z ₁₂ , Z ₁₃ , and Z ₁₄ , the temperature of the entire area of the joining member 130 assembled to the piston assembly is uniformly The temperature can be raised to a temperature close to the melting temperature.

On the other hand, the internal temperatures of the sub-main heating spaces Z ₁₁ , Z ₁₂ , Z ₁₃ and Z ₁₄ are uniformly maintained at the main heating temperature (Temp ₄ ). At this time, the main heating temperature (Temp ₄ ) is formed to be higher than the melting temperature of the joining member 130, and is formed to be, for example, larger than 1000 degrees centigrade and smaller than 1300 degrees centigrade.

The fusing member 130 according to this embodiment may be illustratively a ternary nickel filler metal, in which case the fusing temperature of the fusing member 130 is illustratively from 950 degrees Celsius to 1070 degrees Celsius. The first preheating temperature Temp ₁ , the second preheating temperature Temp ₂ and the third preheating temperature Temp ₃ are set to be lower than the melting temperature of the bonding member 130 from 950 ° C. to 1070 ° C. And is set to be higher than the melting temperature of the main heating temperature (Temp ₄ ).

The connecting member 130 disposed between the first piston portion 110 and the second piston portion 120 of the piston assembly while the piston assembly passes through the main heating step in the internal space of the main heating space Z ₂ , Of the first piston portion 110 and the joint surface 122 of the second piston portion 120 are dispersed into the first piston portion 110 and the second piston portion 120 while being melted, , 123) are welded to each other firmly.

Cooling area (Z _3, Z ₄₎ comprises a first cooling space (Z ₃₎ and the first cooling space (Z ₃₎ second cooling space that is in communication with (Z _4).

The first cooling space Z ₃ communicates with the heating spaces Z ₁ and Z ₂ through the second opening 212 and moves to the first cooling space Z ₃ through the second opening 212. The piston unit is subjected to a first cooling step. The internal temperature of the first cooling space Z ₃ decreases sharply from the front side, that is, from the side of the second opening 212 toward the rear side, that is, toward the second cooling space Z ₄ side. That is, the internal temperature of the first cooling space Z ₃ is reduced from the main heating temperature (Temp ₄ ) to the cooling temperature (Temp ₅ ). At this time, the cooling temperature (Temp ₅ ) may be, for example, 10 to 100 degrees Celsius. Therefore, in the first cooling step, the piston unit undergoes a rapid cooling process.

At this time, in order to rapidly lower the internal temperature of the first cooling space Z ₃ , a low-temperature cooling gas can be supplied to the first cooling space Z ₃ .

The internal temperature of the second cooling space Z ₄ is maintained at the cooling temperature Temp ₅ , and in the second cooling space Z ₄ , the piston unit undergoes the second cooling step. In the second cooling step, the piston unit may be cooled at a relatively low speed as compared with the first cooling step. The second cooling space Z ₄ can communicate with the outside through the third opening 213.

A second length of said one direction of the cooling space (Z ₄₎ is formed longer than the length in the one direction of the first cooling space (Z _3). Therefore, the first cooling space (Z ₃₎ and a second cooling space (Z ₄₎ a case will the piston unit moves at the same speed, and the second cooling space (Z ₄₎ the second cooling step in which cooling is carried out at a May be performed for a longer time than the first cooling step. Illustratively, the time for which one of the piston units stays in the first cooling space Z ₃ can be included in the range of two to four times the same time the piston unit stays in the second cooling space Z ₄ .

Although the cooling spaces Z ₃ and Z ₄ are described as spaces in which the remaining portions except for the second openings 212 and the third openings 213 are closed in the present embodiment, is not formed, the cooling area (Z _3, Z ₄₎ that is configured to form a whole, the open atmosphere is also included in the embodiment of the present invention.

The moving means 220 moves the piston assembly in one direction so that the piston assembly before welding is welded and cooled through the heating spaces Z ₁ and Z ₂ and the cooling spaces Z ₃ and Z ₄ .

The moving means 220 may be a moving device using a conveyor belt as an example. The moving means 220 includes a conveyor belt 211 in which a plurality of the piston assemblies are seated and moved in one direction, a conveyor belt 211 for moving the conveyor belt 211 in one direction And power sections 221 and 223 for providing rotational force. The conveyor belt 211 according to the present embodiment is illustratively capable of moving at a speed of 5 to 30 centimeters per minute.

A plate-shaped seating member 400 is disposed between the upper surface of the conveyor belt 211 and the piston assembly, so that the seating of the piston assembly is stably performed, and damage to the piston assembly can be prevented.

The piston assembly is seated on the conveyor belt 211 in a stacked state in the order of the first piston portion 110, the joining member 130, and the second piston portion 120. That is to say that the first piston part 110 in which the combustion cavity 115 is formed is positioned at the bottom and the second piston part 120 in which the piston skirt 125 and the pin hole 216 are formed is positioned at the top , The piston assembly is arranged and put on the conveyor belt (211). The interface between the first piston portion 110 and the second piston portion 120 is positioned below the center of gravity of the piston assembly, so that more stable transfer of the piston assembly can be achieved.

If the heating spaces Z ₁ and Z ₂ of the piston manufacturing apparatus 200 are formed partially open, the heating spaces Z ₁ and Z _{2 in the} open atmosphere are heated at a high temperature, There is a problem that oxidation may occur on the surface of the piston assembly.

Therefore, the piston manufacturing apparatus 200 performing the piston manufacturing method according to the embodiment of the present invention further includes the mixed gas supply unit 240. The mixed gas supply unit 240 supplies the mixed gas into the heating spaces Z ₁ and Z ₂ and the mixed gas supplied to the heating spaces Z ₁ and Z ₂ flows into the heating spaces Z ₁ and Z ₂ , Inhibits the oxidation of the piston assemblies moving inside, and is discharged to the outside.

The supply flow channel f ₁ of the mixed gas supply unit 240 is illustratively disposed below the gas discharge port (not shown) disposed between the third sub main heating space Z ₂₃ and the fourth sub main heating space Z ₂₄ Lt; / RTI > That is, the supply flow path f ₁ of the mixed gas is disposed on the rear side of the heating spaces Z ₁ and Z ₂ adjacent to the cooling spaces Z ₃ and Z ₄ .

The mixed gas flowing into the heating spaces Z ₁ and Z ₂ flows through the discharge passages f ₁₁ and f ₁₂ toward the first opening portion 211 and the second opening portion 212 in the heating spaces Z ₁ and Z ₂ To the outside.

In this case, the first opening 211 and the second opening 212 or the third opening 213 may be provided with combustion means for removing the hydrogen (for example, Not shown) may be provided. By supplying the mixed gas according to the present embodiment to the heating spaces (Z ₁ , Z ₂ ), the oxidation of the piston assembly during the heating process can be suppressed by being an inert gas in the case of nitrogen and hydrogen being a reducing gas.

In this embodiment, the piston assembly is continuously transferred to the inside of the piston manufacturing apparatus 200 and welded and cooled, thereby further improving the productivity.

Meanwhile, in the case of the piston manufacturing method according to the embodiment of the present invention, since the piston assembly is moved by the moving means 220 and is heated and welded, the matching state of the pistons must be maintained. Therefore, the construction for maintaining the matching state of the piston assembly during the movement will be described in detail below.

8 is a cross-sectional view of the piston assembly held by the jig when the piston assembly is seated in the piston manufacturing apparatus of Fig. 6;

8, in the piston manufacturing process according to the present embodiment, when the piston assembly is assembled and the piston assembly is seated on the conveyor belt 221 of the piston manufacturing apparatus 200, The piston assembly 120 may be installed on the piston assembly so that the second piston portion 120 is pressed toward the first piston portion 110 so that the piston assembly can be stably maintained in the fitted state.

The jig 300 includes a first jig 310 and a second jig 320 formed of a heavy weight metal material.

The first jig 310 is disposed on the side of the center hole 160 of the second piston portion 120 to press the second piston portion 120 toward the first piston portion 110.

The second jig 320 includes a second jig body 321 having a through hole 323 formed therein and a second jig body 321 extending downward from both ends of the second jig body 321, And a pair of pressing portions 322 that are in contact with one surface of the head portion 129 of the main body 120. The second jig body (321) is spaced apart from the piston coupling body by a predetermined distance in a state where the second jig (320) is installed on the piston coupling body. Through the through holes 323 formed in the second jig body 321, the heat of the heating spaces Z ₁ and Z ₂ can be smoothly transferred to the piston assembly.

According to the present embodiment, the first jig 310 of the jig 300 presses the stem of the piston assembly, and the second jig 320 presses the rim of the piston assembly, It is possible to provide a pressing force.

Fig. 9 is a view showing the metal texture size of the piston before and after the piston manufacturing process by the piston manufacturing apparatus of Fig. 6; Fig.

9 (A) is a view showing an optical microscope photograph of a metal structure formed on a partial cross section of the piston assembly before welding the piston 1 according to the present embodiment, and Fig. 9 (B) ) Is subjected to welding and cooling, and then the metal structure formed on a partial cross section of the piston unit is photographed by an optical microscope.

9 (A) and 9 (B), before the manufacturing process according to the piston manufacturing method according to the present embodiment is performed, the metal formed in the first piston portion 110 and / or the second piston portion 120 The grain size of the pearlite structure G1 in the tissue is formed to be the first size W1.

After the above-mentioned manufacturing process, the grain size of the pearlite structure G2 in the metal structure formed on the piston unit is formed to a second size W2.

In this case, the first size (W1) of the second size (W ₂₎ largely formed more, illustratively includes a first size (W ₁₎ is formed of 64 um to 90 um in size, the second size (W ₂₎ is 32 um to 45 um.

It is also confirmed that the hardness of the piston 1 after the manufacturing process according to the piston manufacturing method according to the present embodiment is increased by approximately 2% to 5% with respect to the hardness of the piston assembly before the manufacturing process.

In the piston manufacturing method according to the present embodiment, the particle size of the metal structure of the piston 1 is reduced and the hardness is increased.

FIG. 10 is a view showing a cooling gallery of a piston unit formed by welding a piston assembly in the piston manufacturing apparatus of FIG. 6, and FIG. 11 is an enlarged view of a portion XII of FIG.

10 and 11, a diffusion layer 150 is formed on the inner surface of the cooling gallery 140 of the piston 1 manufactured by the manufacturing method according to the present embodiment, in which a part of the joining member 130 is diffused, .

The diffusing layer 150 includes a dissimilar metal of a nickel-based alloy included in the joining member 130. The diffusion layer 150 is formed on the inner surface of the cooling gallery 140, Corrosion resistance can be improved.

On the other hand, the piston body of the piston 1 is formed with a bonding interface I which is parallel to the upper surface of the piston body and penetrates through the cooling gallery 140.

The bonding interface I is a portion formed by joining the bonding surfaces of the first piston portion 110 and the second piston portion 120 while the bonding member 130 is melted and diffused and the center of the bonding interface I The density of the dissimilar metal, for example, nickel, which is different from the material of the piston body formed of the steel material, becomes smaller toward the outer side of the bonding interface (B).

The following is an exemplary analysis of the components of the bonded interface of the piston of FIG.

location C (%) Si (%) Fe (%) Ni (%) A 1.83 8.98 14.34 74.56 B 1.36 2.21 42.13 54.3

That is, in the piston manufacturing method according to the present embodiment, the metal diffusion at the bonding interface I at which the bonding member 130 is disposed is smooth and the first piston portion 110 and the second piston portion 120 can be stably welded.

12 is a view illustrating a method of manufacturing a piston for a vehicle engine according to an embodiment of the present invention.

Referring to FIG. 12, the method for manufacturing a piston for a vehicle engine according to the present embodiment includes aligning a first piston 110, a joining member 130, and a second piston 120 to form a piston assembly Step S100 is performed.

Next, a jig 300 is installed on the assembled piston assembly, and a jig installation step (S200) is performed to maintain the aligned state of the piston assembly stably.

The piston assemblies are then placed on the conveyor belt 221 of the manufacturing apparatus 200 and then heated in the heating spaces Z ₁ and Z ₂ of the manufacturing apparatus 200 to consecutively weld the piston assemblies, (S300).

The preheating step of heating the piston assembly up to just before the melting temperature of the joining member 130 in the piston welding step S300 and the preheating step of heating the piston assembly preheated in the preheating step to the fusion of the joining member 130 The main heating step of heating the first and second piston parts 110 and 120 to the main heating temperature higher than the temperature is performed so that the first piston part 110 and the second piston part 120 are welded to each other by the diffusion of the joining member 130.

At this time, the main heating temperature is higher than the melting temperature of the joining member 130 and is lower than the melting temperature of the base material, that is, the first piston portion 110 and the second piston portion 120.

Next, a piston cooling step (S400) for cooling the piston unit formed by welding the piston assembly is performed.

A first cooling step for rapidly cooling the piston unit heated from the main heating step to the main heating temperature in a piston cooling step (S400), and a second cooling step for cooling the piston unit cooled in the first cooling step The second cooling step is performed.

Thereafter, the engaging portion 127 protruding toward the combustion cavity 115 side of the piston unit that has been cooled is removed, and a piston processing step (S500) for processing the piston unit is performed. The piston machining step (S500) may be, for example, cutting. At this time, the piston machining step (S500) may be referred to as a step of removing the engagement portion.

In the meantime, although the present embodiment is described as including a piston machining step (S500) in which the engaging portion 127 is removed by a cutting process or the like in which the engaging portion 127 is removed, When the assembled state of the piston part 110 and the second piston part 120 is maintained, the engaging part 127 may not be removed in the piston processing step S500.

According to the proposed embodiment, the upper piston part and the lower piston part can be welded without flashing by manufacturing a piston made of steel by the brazing method.

Further, as the piston manufacturing process is performed in the open atmosphere, the welding of the piston can be continuously performed, and the manufacturing efficiency of the piston can be increased.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Of course.

Hereinafter, other embodiments of the present invention will be described. The embodiments described below are the same as those of the piston manufacturing method for a vehicle engine described above with reference to Figs. 1 to 12, .

13 is a view showing a state in which a piston assembly is assembled in a process of manufacturing a piston for a vehicle engine according to another embodiment of the present invention.

Referring to FIG. 13, the piston 5 assembled in the assembling step according to the method for manufacturing a piston for a vehicle engine according to the present embodiment includes a first piston 510 and a second piston 520, (Not shown) disposed between the first piston portion 510, the second piston portion 520, the first piston portion 510 and the second piston portion 520 is assembled, The piston portion 510 and the second piston portion 520 are welded.

The first piston portion 510 includes a first groove 512 and a second groove 513 and a first groove disposed between the first and second jaws 512 and 513 And the second piston portion 520 includes a third joint surface 522 facing the first joint surface 512, a fourth joint surface 523 facing the second joint surface 513, And a second groove disposed between the face 522 and the fourth abutment surface 523. In a state where the first piston portion 510 and the second piston portion 520 are welded, illustratively brazed, the first groove and the second groove communicate with each other to form a cooling gallery 540.

The first piston portion 510 of the piston 5 according to the present embodiment further includes a latching portion 517. [

The engaging portion 517 is disposed on the rim adjacent to the second abutment surface 513 disposed on the center side of the first piston portion 510 and is preferably in a direction intersecting the plane formed by the second abutment surface 513, As shown in Fig. That is, the engaging portion 517 is formed at a position closer to the center of the first piston portion 510 than the second abutment surface 513, and the second piston portion 510 is moved toward the second piston portion 520 from the first piston portion 510 And is protruded in a vertical direction.

The engaging portion 517 is engaged with the inner rim of the second piston portion 520, that is, the rim adjacent to the fourth abutment surface 523, in the state where the first piston portion 510 and the second piston portion 520 are assembled, . Illustratively, the locking portion 517 may be formed in an annular shape corresponding to the annular shape of the second joining surface 513 formed by the adjacent rim.

On the other hand, the positions of the first joint surface 512, the second joint surface 513, the third joint surface 522 and the fourth joint surface 524 of the piston 5 according to the present embodiment are changed from each other . That is, the first joint surface 512 and the third joint surface 522 of the piston 5 according to the present embodiment are adjacent to the outer circumferential sides of the first piston portion 510 and the second piston portion 520, And the second joint surface 513 and the fourth joint surface 523 are disposed adjacent to the center sides of the first piston portion 510 and the second piston portion 520 respectively, 512 and the third joint surface 522 are disposed adjacent to the center sides of the first piston portion 510 and the second piston portion 520 respectively and the second joint surface 513 and the fourth joint surface 523 may be disposed adjacent to the outer circumferential sides of the first piston portion 510 and the second piston portion 520, respectively.

FIG. 14 is a view showing a state in which a piston assembly is assembled in a process of manufacturing a piston for a vehicle engine according to another embodiment of the present invention. FIG. 15 is a cross- Fig.

Referring to FIG. 14, the piston 6 assembled in the assembling step according to the method for manufacturing a piston for a vehicle engine according to this embodiment includes a first piston 610, a second piston (Not shown) disposed between the first piston portion 610, the second piston portion 620, the first piston portion 610, and the second piston portion 620 is assembled The first piston portion 610 and the second piston portion 620 are welded to each other.

The first piston portion 610 has a first joint surface 612 and a second joint surface 613 and the second piston portion 620 has a third joint surface 622 and a fourth joint surface 623, . A cooling gallery 640 is formed between the first piston portion 610 and the second piston portion 620 while the first piston portion 610 and the second piston portion 620 are welded to each other.

The second piston portion 620 further includes an engagement portion 627.

The engaging portion 627 is disposed on the rim adjacent to the third abutting surface 622 disposed on the outer peripheral side of the second piston portion 620 and is preferably in a direction intersecting the plane formed by the third abutting surface 622, As shown in Fig. That is, the engaging portion 627 is formed at a position protruding to the outer circumferential side of the second piston portion 620 more than the third abutment surface 622, and the first piston portion 610 from the second piston portion 620 As shown in Fig.

The engaging portion 627 is engaged with the outer peripheral surface of the first piston portion 610, that is, the edge adjacent to the first abutting surface 612 in the state where the first piston portion 610 and the second piston portion 620 are assembled Wrapped. Illustratively, the engagement portion 627 may be formed in an annular shape corresponding to the annular shape formed by the third contact surface 622 adjacent to the rim, that is, the outer periphery of the second piston portion 620.

On the other hand, at the corner portion of the other piston portion 610 facing the engaging portion 627 and the engaging portion 627, a round portion formed with rounded corners and / or a cut portion where the corners are cut is formed.

The round portion is formed on each of the engaging portion 627 side of the piston 6 and the corner portion of the first piston 610 facing the engaging portion 627 of the piston 6 according to the present embodiment.

Hereinafter, the configuration will be described in detail.

Referring to FIG. 15, a bonding interface I is formed between the first piston portion 610 and the second piston portion 620 of the piston 6 manufactured according to the present embodiment. A first round portion 629 having a predetermined radius of curvature is formed between the third abutment surface 622 of the second piston portion 620 and the engaging portion 627 and the first round portion 629 of the first piston portion 620 A second round portion 619 having a predetermined radius of curvature is formed at the edge of the rim adjacent to the bonding surface 612. The second round portion 619 is disposed to face the second round portion 629 while the first piston portion 610 and the second piston portion 620 are assembled or welded.

The curvature radii of the first round portion 629 and the second round portion 619 are different from each other.

More specifically, the radius of curvature of the second round portion 619 is formed to be larger than the radius of curvature of the first round portion 629. That is, the curvature of the second round portion 619 is formed to be smaller than the curvature of the first round portion 629.

When the corner portion of the first piston portion 610 and the corner portion of the second piston portion 620 are in contact with each other, the first piston portion 610 and the other portion of the second piston portion 620, except for the corner portions, The piston 6 can be welded poorly. Therefore, as the curvature radius of the first round portion 629 in which the engaging portion 627 of the piston 6 according to the present embodiment is formed is smaller than the radius of curvature of the second round portion 629, The second round portion 619 side can be prevented from directly contacting the first round portion 629 in the welding process.

On the other hand, on the other side of the third joint surface 622 of the second piston portion 610, that is, on the side of the opposite side of the edge where the second round portion 619 is formed, a cut portion 628 cut by an oblique line is formed .

16 is a view showing a state in which a piston assembly is assembled in a process of manufacturing a piston for a vehicle engine according to another embodiment of the present invention.

Referring to Figure 16, the piston 7 according to the present embodiment includes a first piston 710 having a first abutment surface 712 and a second abutment surface 713, a third abutment surface 732, And a cooling gallery 740 is formed between the first piston portion 710 and the second piston portion 720. The second piston portion 720 has a fourth joint surface 723. On the other hand, a bonding member (not shown) is disposed between the bonding surfaces 712, 713, 722, and 723 of the first piston portion 710 and the second piston portion 720. However, The joining member will be omitted.

In the method of manufacturing a piston for a vehicle engine according to the present embodiment, the engaging portion 750 formed of a separate member detachable from the piston 7 is inserted into the first piston portion 710 and the second piston portion 710, So that the assembled mating state of the first electrode 720 is maintained.

More specifically, the latching unit 750 includes a latching body 751 formed in an annular shape and having a through hole 752 formed at the center thereof.

The outer diameter of the engaging portion body 751 is larger than the outer diameter of the first piston side joint surface rim 719 adjacent to the second joint surface 713 disposed on the center side of the joint surfaces 712 and 713 of the first piston portion 710, Side joint surface frame 729 adjacent to the fourth joint surface 723 disposed on the center side of the joint surfaces 722 and 723 of the second piston portion 720 and the inner surface of the second piston- .

In order to manufacture the piston 7, in the state where the first piston portion 710, the second piston portion 720, and the piston assembly having the joining member assembled therein have the engagement portion 750, the engagement portion 750 Is simultaneously brought into contact with the first piston side joint surface rim 719 and the second piston side joint surface rim 729 simultaneously.

The engaging portion 750 is disposed on the side of the combustion cavity 715 formed on the side of the first piston portion 710 and is seated on the seating surface 728 of the second piston portion 720. The seating surface 728 is formed in a bent shape with respect to the second piston side joint surface rim 729 and the seating surface 728 is formed with the fourth joint surface 723 side by side. That is, the seating surface 728 is formed to have a stepped height with respect to the fourth bonding surface 723, and a first piston side bonding surface frame 729 is formed between the seating surface 728 and the fourth bonding surface 723, .

According to this embodiment, in the manufacturing process of the piston 7, since the detachable latching portion 750 is provided, a separate cutting process for removing the latching portion 750 is not required, and the first piston portion 710 and the second piston portion 720 can be simplified.

According to the method for manufacturing a piston for a vehicle engine according to the present embodiment, the engaging portion 750 is rotated in a piston working step (S500), that is, in the engaging portion removing step, a tool such as a separate jig or the welded piston unit is reversed Or a vibration of a predetermined magnitude may be applied to the piston unit to remove the piston unit from the piston unit.

17 is a view showing a state in which a piston assembly is assembled in a process of manufacturing a piston for a vehicle engine according to a method for manufacturing a piston for a vehicle engine according to another embodiment of the present invention.

17, the piston 8 according to the present embodiment includes a first piston portion 810 having a first abutment surface 812 and a second abutment surface 813, a third abutment surface 822, And a cooling gallery 840 is formed between the first piston portion 810 and the second piston portion 820. The first piston portion 810 and the second piston portion 820 have a fourth contact surface 823. The present embodiment differs from the piston manufacturing method described with reference to Fig. 16 in the configuration of the latching portion 850, and the other configurations are substantially the same, and therefore, the characteristic portions of this embodiment will be mainly described below .

In the process according to the piston manufacturing method according to the present embodiment, the outer circumferential surface of the engaging portion body 851 is simultaneously abutted with the first piston side joint surface rim and the second piston side joint surface rim joint surface rim simultaneously And a height corresponding to the height of the combustion cavity 815. Illustratively, if the depth of the combustion cavity 815 is greater than the thickness of the first piston portion 810, that is, the height of the first piston portion 810, the engagement portion 850 may be positioned between the first piston portion 810 The thickness in the up-and-down direction may be greater than the thickness in the up-and-down direction.

The engaging portion 850 is disposed on the side of the combustion cavity 815 formed through the first piston portion 810 in a state where the engaging portion 850 is mounted on the piston assembly, Is disposed in parallel with one surface of the first piston portion 810. That is, one surface of the engaging portion body 851 forms substantially the same plane as one surface of the first piston portion 810. At this time, the rear surface of the engaging portion body 851 is supported by the second piston portion 820.

According to the proposed embodiment, when the one face of the first piston portion 810 is seated on the seating member 400 and is pulled into the piston manufacturing apparatus 200 and welded, the first piston portion 810, And the one side of the latching part 850 are simultaneously brought into contact with the seating member 400, thereby making it possible to make the seating of the piston assembly with respect to the seating member 400 more stable.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Of course.

1, 5, 6, 7, 8: Piston
110, 510, 610, 710, 810:
120, 520, 620, 720, 820: second piston part 130:
140, 540, 640, 740, 840: Cooling gallery 200: Piston manufacturing device
210: piston manufacturing apparatus body 220: conveying means
Z ₁ : Preheating space Z ₂ : Main heating space
Z ₃ : first cooling space Z ₄ : second heating space
300: jig 310: first jig
320: second jig 400: seating member

Claims (13)

A method of manufacturing a piston for a vehicle engine,
A first piston portion spaced apart from each other and extending in a circumferential direction and having at least two abutment surfaces, a joining member, and a second piston portion spaced apart from each other and having at least two circumferentially extending abutment surfaces to form a piston assembly Piston assembly step;
A piston welding step of heating the assembled piston assembly to weld the first piston part, the joining member and the second piston part in an open atmosphere; And
And a piston cooling step of cooling the piston unit formed by welding the first piston part, the joining member and the second piston part,
Wherein the piston assembly further includes a latching portion for holding the assembled position of the first piston portion and the second piston portion,
Further comprising a step of removing the engaging portion in the cooled piston unit,
Wherein the piston welding step comprises a piston manufacturing device including a heating space partially open, a heating means providing heat inside the heating space, and a moving means moving in one direction within the heating space,
In the piston welding step, the piston assembly is heated by the moving means while being moved at a predetermined speed in one direction in the heating space,
Wherein the engaging portion is disposed on a rim adjacent to any one of the pair of abutment surfaces formed on the second piston and disposed on the center side of the second piston portion, And is protruded in a direction intersecting the plane formed by the joining surfaces,
Wherein the engaging portion is exposed to the outside through the combustion cavity while being inserted into a combustion cavity formed at the center of the first piston. The method according to claim 1,
Wherein an outer diameter of the engaging portion is formed to have a size corresponding to a diameter of the combustion cavity so that the engaging portion surrounds the inner rim of the first piston portion. delete delete The method according to claim 1,
A first round portion having a predetermined radius of curvature is formed between the engaging portion and either one of the abutting surfaces or between the engaging portion and the other abutting surface,
Wherein a cut portion formed in an oblique line or a second round portion having a preset radius of curvature is formed at an edge portion of the piston portion where the latch portion is not formed, facing the round portion. 6. The method of claim 5,
Wherein the radius of curvature of the second round portion is larger than the radius of curvature of the first round portion. delete delete delete The method according to claim 1,
Wherein the piston welding step comprises:
A preheating step of heating the piston assembly assembled at room temperature from the room temperature to a preheating temperature lower than a melting temperature of the joining member; And
Heating the piston assembly heated up to the preliminary heating temperature in the preheating step to a main heating temperature higher than the melting temperature of the joining member so that the first piston portion, the joining member, and the second piston And a main heating step of welding the parts to each other. The method according to claim 1,
Wherein the second piston portion includes a piston skirt and a piston pinhole,
Wherein the plurality of piston assemblies are continuously moved by the moving means in a state in which the first piston portion, the joining member, and the second piston portion are stacked in this order and the piston assembly is formed. For producing a piston. delete The method according to claim 1,
And a jig mounting step for mounting the jig so that the first piston, the joining member, and the second piston are maintained in an aligned state in a state where the piston assembly is formed,
The jig,
And a pressing portion extending downward from both ends of the jig body and contacting one edge of the second piston portion,
Wherein the jig body is spaced apart from the piston assembly when the jig is installed.

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